Objectives: (a) The studies in human subject are proposed to investigate the role of central cholinergic system in extrapyramidal disorders by (1) measuring acetylcholine (ACh) and choline (Ch) in spinal and ventricular fluid (2) evidence of therapeutic efficacy of pilocarpine in dyskinesia. (b) Animals studies of certain proposed pathological roles of ACh that cannot be studid in human subjects will be investigated in laboratory animals by (1) localisation of dopamine (DA) and ACh receptors in the striatum (2) measuring ACh turnover after the degeneration of the nigrostriatal pathway and after the administration of antiparkinsonian drugs and phenothiazines and (3) determining the effect of cholinergic drugs on phenothiazine induced modifications in ACh metabolism. All these studies are designed to determine the role of central cholinergic neurons in extrapyramidal functions.